1. Field of the Invention
The present invention relates to a film scanner capable of reading an image on an advanced photo system (APS) film having a new film format, or images on other types of films.
2. Related Background Art
Conventional film scanners for inputting film images to a personal computer have been developed mainly for 35 mm films (also called "135 film"). In reading an image with a scanner, a film scanner is first operated at low resolution and at high speed and the whole image is once displayed (previewed) on a personal computer. Thereafter, a read area in the preview is designated, and the image in this read area is newly read by the film scanner to be sent to the personal computer.
A conventional film scanner will be described with reference to FIG. 28 showing the structure thereof.
Reference numeral 2801 represents a light source. Reference numeral 2802 represents a film holder for holding a film or transparent original, the film holder being movable in the Y-direction as indicated in FIG. 28. Reference numeral 2803 represents a focussing lens system, and reference numeral 2804 represents a CCD linear image sensor (also called a CCD linear sensor and called hereinafter a linear image sensor). The longitudinal direction of the linear image sensor 2804 is disposed along the X-direction as indicated in FIG. 28. With the above position relation, the main scan direction along the longitudinal direction of the linear image sensor 2804 is perpendicular to the sub scan direction along the motion direction of the film folder 2802. A color image may be read in various ways with the following relations between the light source 2801 and linear image sensor 2804.
______________________________________ Light source CCD Read ______________________________________ a) White color 3 lines Simultaneous RGB b) Three colors 1 line RGB Time-division (RGB emission) c) White color 1 line RGB Time-division (RGB filters) ______________________________________
Each of these methods has merits and demerits and is tried to be properly selected. In the following, the above combination a) will be described.
Reference numeral 2805 represents an analog image processing circuit which executes gain setting and clamping of an analog image signal output from the linear image sensor 2804. Reference numeral 2806 represents an A/D converter for converting an analog signal into a digital signal. Reference numeral 2807 represents an image processing unit composed of gate arrays which can execute at high speed various processes including image processing and CCD drive pulse processing. Reference numeral 2808 represents a line buffer for temporarily storing image data. Reference numeral 2809 represents an interface unit used for communications with external equipment 2810 such as a personal computer. Reference numeral 2811 represents a system controller in which the whole sequence of the film scanner is stored, the system controller executing various operations in accordance with instructions from the external equipment 2810. Reference numeral 2812 represents a CPU bus for the interconnection among the system controller 2811, image processing unit 2807, line buffer 2808 and interface unit 2809, the CPU bus being composed of an address bus and a data bus.
Reference numeral 2813 represents a subscanning motor for moving the film holder 2802 in the sub scan direction, this motor being a stepping motor in this example. Reference numeral 2814 represents a subscanning motor driver for driving the subscanning motor 2813 in response to an instruction from the system controller 2811. Reference numeral 2815 represents a subscanning position detection unit for detecting a reference position of the sub scan, this unit being a photo interrupter which detects a projection formed on the film folder 2802. Reference numeral 2816 represents a light source turn-on circuit for turning on the light source 2801.
The conventional film scanner has been constructed as above. Image data is input to the external equipment 2810 such as a personal computer through communications between software (hereinafter called firmware) embedded in the system controller 2811 and software (hereinafter called driver software) for operating the film scanner from the external equipment 2810 such as a personal computer.
This image data transfer process will be briefly described with reference to the flow chart shown in FIG. 29. It is assumed now that the file scanner and the external equipment 2810 have their power turned on already and that under the running state of firmware and driver software, a user has inserted a film into a predetermined location.
At Step S2901, the user enters a preview instruction from the external equipment 2810. Then, the external equipment 2810 transmits, to the firmware side, designated information including a film type, a read area (all screen in this case) and a read resolution (low resolution in this case).
At Step S2902, the firmware sets the designated information including the film type, read area and read resolution for the preparation of succeeding operations.
At Step S2903, the system controller 2811 reads information on the subscanning position detection unit 2815, and controls the subscanning motor 2813 to move the film to an initial position.
At Step S2904, the system controller 2811 issues a light source turn-on instruction to the light source turn-on circuit 2816 to turn the light source 2801 on.
At Step S2905, the system controller 2811 issues an instruction for outputting timing pulses (such as CCD drive pulse and RAM address control pulse) in order to read one line data.
At Step S2906, image data of each line is read during a predetermined exposure time and the subscanning motor 2813 is driven at a predetermined speed. Thereafter, the image processing unit 2807 performs image processing to output image data to the external equipment 2810.
If the image read area has been fully scanned at Step S2907, the system controller 2811 drives the subscanning motor 2813 to restore the initial position. The light source 2801 is turned off, and all functions of the film scanner are stopped.
At Step S2908, the firmware of the system controller 2811 enters a routine of waiting for the next command.
At Step S2909, the external equipment 2810 receives the image data, and sequentially displays it to show the user the whole film image.
At Step S2910, after viewing the preview image data, the user again sets image fetching conditions to instruct a next substantial or main scan. Similar to Step S2901, information designated by the user, including the film type, read area (area designated by the user in this case) and/read resolution (resolution designated by the user in this case), is transmitted to the firmware side.
At Step S2911, the firmware of the system controller 2811 receives the read conditions, and the operations from Step S2902 to Step S2908 are executed under the substantial or main scan conditions. The image data sent to the external equipment 2810 at Step S2912 is displayed by using the driver software and can be stored in a storage medium (such as a hard disk, a magnetooptical disk and a floppy disk).
With the above conventional techniques, however, three types of photographing modes recorded magnetically on an APS film are not considered at all when reading image information of the APS film. Therefore, the conventional techniques can deal with only one photographing mode of reading the broadest area of a film. Therefore, in a photographing mode of photographing an image in a narrower area of a film frame, a user is required to trim the image read area, or otherwise the image data is possibly read from the broadest area.